I see what you're saying, but there also wasn't a great angle to see into the truck. It's a good theory, but I'm guessing it's not. But, if he's not Tarrlock, how the hell did he resist blood-bending? I'll admit the there is a chance it's Tarrlock, you've persuaded me somewhat, but I just don't think it is.

In his theory, the whole thing didn't happen. He didnt' resist blood-bending. He didn't took away Tarrlock's bending. Everything was just what he wanted Korra to think. Amon has used Korra before to send messages and news to the others.